Deep bass sound booster device

ABSTRACT

A deep bass sound booster device comprises a high-pass filter to which an input sound signal is fed and which permits only a frequency component higher than a predetermined frequency to pass through so as to output a resulting signal, a bass booster to which the input sound signal is fed and which amplifies only a frequency component lower than the predetermined frequency and attenuates another frequency component so as to output a resulting signal, a switch to which the signal output from the bass booster is fed at one end and which, when turned on, outputs that signal at another end, and an adder to which the signal output from the high-pass filter is fed and to which the signal output from the switch is fed, the adder adding together those two signals and outputting a resulting signal.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a deep bass sound booster devicethat reproduces a powerful sound having emphasized bass.

[0003] 2. Description of the Prior Art

[0004]FIG. 7 shows a block diagram of a conventional deep bass soundbooster device. Bass boosters 101 and 201, having a gain-frequencyrelationship as shown in FIG. 8, amplify a predetermined frequency band.

[0005] When sound is reproduced with headphones through output terminalsH_(L) and H_(R), a bass-frequency sound is depressed due to structure ofthe headphones. Therefore, it is necessary to compensate this with apre-arranged gain-frequency property. When headphones are used, this isachieved by selecting a property of the bass boosters 101 and 201 asshown in FIG. 8 with a microprocessor or the like used in a systemhaving a deep bass sound booster device. When loudspeakers are used, aproperty shown in FIG. 6 is selected.

[0006] When reproducing the sound with loudspeakers, left-channel andright-channel stereo signals that are fed through input terminals IN_(L)and IN_(R) from a sound source are input to high-pass filters 102 and202 after passing through the bass boosters 101 and 201 respectively.When reproducing the sound with headphones, the stereo signals arereproduced with left and right headphones that are connected to theoutput terminals H_(L) and H_(R) respectively without passing throughthe high-pass filters 101 and 202.

[0007] Each of the high-pass filters 102 and 202 has a gain-frequencyrelationship as shown in FIG. 3 and permits only a frequency componenthigher than a cutoff frequency fc (e.g. 100 Hz) to pass through whensignals are fed from the bass boosters 101 and 201. The signals outputfrom the high-pass filters 102 and 202 are converted into audio soundswith left and right mid- to high-range loudspeakers that are connectedto output terminals S_(L) and S_(R) respectively.

[0008] An adder 301 outputs signals after adding the left-channel andright-channel stereo signals together that are fed to the inputterminals IN_(L) and IN_(R) respectively from the sound source. A bassbooster 302, having a gain-frequency relationship as shown in FIG. 4,amplifies a predetermined frequency band T and attenuates anotherfrequency band in the signals that are fed from the adder 301 beforefeeding out as a resulting signal. The signal output from the bassbooster 302 is then converted into an audio sound with a bass(low-range) loudspeaker that is connected to an output terminal S_(B).

[0009] As described above, when the headphones are used, thegain-frequency relationship between the reproduced sound and the soundsource will be such a curve as shown in FIG. 8. When the loudspeakersare used, the gain-frequency relationship will be such a curve as shownin FIG. 5. In either case, it is possible to reproduce a powerful audiosound having emphasized bass.

[0010] However, according to the aforementioned conventional deep basssound booster device, it is necessary to arrange individual bassboosters, for example, the bass boosters 101 and 201 for outputting toheadphones and the bass booster 302 for outputting to loudspeakers. As aresult, this requirement causes an increase in circuit size and cost.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a deep basssound booster device that can be made smaller in size and economically.

[0012] To achieve the above object, according to one aspect of thepresent invention, a deep bass sound booster device comprises, ahigh-pass filter to which an input sound signal is fed and which permitsonly a frequency component higher than a predetermined frequency to passthrough so as to output a resulting signal, a bass booster to which theinput sound signal is fed and which amplifies only a frequency componentlower than the predetermined frequency and attenuates another frequencycomponent so as to output a resulting signal, a switch to which thesignal output from the bass booster is fed at one end and which, whenturned on, outputs that signal at another end, and an adder to which thesignal output from the high-pass filter is fed and to which the signaloutput from the switch is fed, the adder adding together those twosignals and outputting a resulting signal.

[0013] In this structure, when the switch is turned on, the sound sourcesignal is processed so that the resulting signal output from the adder,as shown in FIG. 5, includes a signal consisting of amplified low-rangefrequencies and attenuated mid-to high-range frequencies and a signalconsisting of attenuated low-range frequencies. On the other hand, whenthe switch is turned off, the resulting signal output from the adderincludes a signal consisting of amplified low-range frequencies andattenuated mid- to high-range frequencies.

[0014] Therefore, when headphones that are connected to an output sideof the adder are used to reproduce an audio sound, the switch is turnedon. Instead, when mid- to high-range loudspeakers that are connected tothe output side of the adder and a bass loudspeaker that is connected toan output side of the bass booster are used to reproduce an audio sound,the switch is turned off. In this way, a single bass booster can beshared between headphones and loudspeakers so as to reproduce a powerfulaudio sound having emphasized bass.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] This and other objects and features of the present invention willbecome clear from the following description, taken in conjunction withthe preferred embodiments with reference to the accompanying drawings inwhich:

[0016]FIG. 1 is a block diagram showing a deep bass sound booster deviceof a first embodiment of the invention;

[0017]FIG. 2 is a block diagram showing a deep bass sound booster deviceof a second embodiment of the invention;

[0018]FIG. 3 is a chart showing a gain-frequency relationship of ahigh-pass filter shown in FIG. 1;

[0019]FIG. 4 is a chart showing a gain-frequency relationship of a bassbooster shown in FIG. 1;

[0020]FIG. 5 is a chart showing a gain-frequency relationship of thesound reproduced with the deep bass sound booster device;

[0021]FIG. 6 is a chart showing another gain-frequency relationship ofthe high-pass filter shown in FIG. 1;

[0022]FIG. 7 is a block diagram showing a conventional deep bass soundbooster device; and

[0023]FIG. 8 is a chart showing a gain-frequency relationship of theconventional deep bass sound booster.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present invention will bedescribed with reference to the accompanying drawings. FIG. 1 is a blockdiagram showing a deep bass sound booster device of a first embodimentof the present invention. Processing blocks 1 and 2 are blocks forprocessing left-channel and right-channel mid- to high-range audiosignals respectively. Each of high-pass filters 11 and 21 has again-frequency relationship as shown in FIG. 3 and permits only afrequency component higher than a cutoff frequency fc (e.g. 100 Hz) topass through when signals are fed from input terminals IN_(L) and IN_(R)respectively. The signals output from the high-pass filters 11 and 21are then fed to adders 12 and 22 respectively.

[0025] An adder 31 outputs a resulting signal after adding together theleft-channel stereo signal that is fed to the input terminal IN_(L) froma sound source and the right-channel stereo signal that is fed to theinput terminal IN_(R) from the sound source. A bass booster 32, having again-frequency relationship as shown in FIG. 4, outputs a signal afteramplifying a frequency component in a predetermined frequency band T andattenuating another frequency component when the signal output from theadder 31 is fed in. The signal output from the bass booster 32 is thenfed to adders 12 and 22 after passing through switches 13 and 23respectively. Furthermore, an output side of the bass booster 32 isconnected to an output terminal S_(B) to which a bass (low-range)loudspeaker is to be connected.

[0026] An output side of the adder 12 is connected to an output terminalS_(L) to which a left-channel mid- to high-range loudspeaker is to beconnected and is also connected to an output terminal H_(L) to which aleft-channel headphone is to be connected. An output side of the adder22 is connected to an output terminal S_(R) to which a right-channelmid- to high-range loudspeaker is to be connected and is also connectedto an output terminal H_(R) to which a right-channel headphone is to beconnected.

[0027] In this structure, each related property is designed so thatsubstantially an identical property curve as shown in FIG. 5 is realizedwhen a gain-frequency curve of the high-pass filter 11 or 21 as shown inFIG. 3 and that of the bass booster 32 as shown in FIG. 4 are addedtogether.

[0028] According to the structure as described above, when the switches13 and 23 are turned on, a signal output from the adder 12 becomes a sumof combined signals that are output from the high-pass filter 11 and thebass booster 32. At the same time, a signal output from the adder 22becomes a sum of combined signals that are output from the high-passfilter 21 and the bass booster 32. On the other hand, when said switchesare turned off, the adders 12 and 22 output only those signals that arefed from each of the high-pass filters 11 and 21.

[0029] As a result, if a system having the deep bass sound boosterdevice is designed so as to turn on the switches 13 and 23 by switchingmeans when headphones are connected to the output terminals H_(L) andH_(R), and to turn off the switches 13 and 23 by the switching meanswhen mid- to high-range loudspeakers and a bass loudspeaker areconnected to the output terminals S_(L), S_(R), and S_(B) respectively,it becomes possible to reproduce a powerful sound having emphasized bassbecause a similar acoustic gain-frequency relationship as shown in FIG.5 is realized in both cases. Said switching means includes using, forexample, a microprocessor and switching transistors or the like providedin the system in which the deep bass sound booster device of the presentinvention is mounted. Another example of the switching means includesusing mechanical or electrical contacts provided by jacks or connectorsused for connecting the headphones or loudspeakers, or using manuallyoperated switches provided in the system. In this embodiment, a singlebass booster 32 that is shared between outputs to the headphones andloudspeakers contributes to realizing a compact circuit and aneconomical device.

[0030] Furthermore, in the above-mentioned embodiment, if an adjustableinput level to the bass booster 32 is required, the device can beconfigured with a buffer circuit so as to arrange the high-pass filters11 and 21 to have an additional flat gain-frequency relationship (zerogains regardless of frequencies) as shown in FIG. 6. In thisconfiguration, it is desirable for the device to switch over to the flatgain-frequency relationship curve when the input level to the bassbooster 32 is muted while reproducing sound with headphones. It is,therefore, possible to prevent an uncomfortable problem of an acousticsound without bass from being reproduced with headphones, which iscaused otherwise when the input level is adjusted too low.

[0031] On the other hand, in the above-described case when usingloudspeakers, it is also possible to arrange the device for limiting theadjustable input level so as to prevent the bass signal that is outputfrom the bass booster 32 from falling below the input level. In thisarrangement, it is also possible to prevent the uncomfortable problem ofan acoustic sound without bass from being reproduced, without arrangingand switching to an additional property of the high-pass filters 11 and21 in accordance with the input level adjusted and given to the bassbooster 32.

[0032]FIG. 2 is a block diagram showing a deep bass sound booster deviceof a second embodiment of the invention. As shown in FIG. 2, processingblocks 10 and 20 are blocks for processing left-channel andright-channel mid- to high-range audio signals respectively. It is alsopossible to arrange the device so that the right and left channels haveindividual bass boosters 14 and 24 (the same bass booster as used forthe bass booster 32 in FIG. 1) so as to output a bass sound with a bassloudspeaker after an adder 33 adds together the signals output from thebass boosters 14 and 24. In this embodiment, headphones can reproduce apowerful sound with high fidelity, because each individual bass signalin the left and right channels is reproduced without being addedtogether.

[0033] In the case in which a sound source is limited to a monauralsignal, such a device as shown in FIG. 1 but excluding the filter 11 (or21), the adder 12 (or 22), the switch 13 (or 23), and the adder 31 isalso possible.

[0034] As previously described, according to the deep bass sound boosterdevice in the present invention, a single bass booster is shared betweenloudspeakers and headphones, thereby contributing to realizing a reducedcircuit size and cost.

What is claimed is:
 1. A deep bass sound booster device comprising: ahigh-pass filter to which an input sound signal is fed and which permitsonly a frequency component higher than a predetermined frequency to passthrough so as to output a resulting signal; a bass booster to which theinput sound signal is fed and which amplifies only a frequency componentlower than the predetermined frequency and attenuates another frequencycomponent so as to output a resulting signal; a switch to which thesignal output from the bass booster is fed at one end and which, whenturned on, outputs that signal at another end; and an adder to which thesignal output from the high-pass filter is fed and to which the signaloutput from the switch is fed, the adder adding together those twosignals and outputting a resulting signal.
 2. A deep bass sound boosterdevice as claimed in claim 1, wherein the switch is turned on when thesignal output from the high-pass filter and the signal output form thebass booster are added together and fed out of the deep bass soundbooster device, and the switch is turned off when the signal output fromthe high-pass filter and the signal output form the bass booster areseparately fed out of the deep bass sound booster device.
 3. A deep basssound booster device comprising: a first adder to which two input soundsignals are fed and which adds those two signals together and outputs aresulting signal; a bass booster to which the signal output from thefirst adder is fed and which amplifies only a frequency component lowerthan a predetermined frequency and attenuates another frequencycomponent so as to output a resulting signal as a second sound outputsignal; a second output terminal by way of which the signal output fromthe bass booster is fed out of the deep bass sound booster device; andtwo processing blocks, each comprising: a high-pass filter to which oneof the two input sound signals is fed and which permits only a frequencycomponent higher than the predetermined frequency to pass through so asto output a resulting signal as a first sound output signal; a switch towhich the signal output from the bass booster is fed at one end andwhich, when turned on, outputs that signal at another end; a secondadder to which the signal output from the high-pass filter is fed and towhich the signal output from the switch is fed, the second adder addingtogether those two signals and outputting a resulting signal; and afirst output terminal by way of which the signal output from the secondadder is fed out of the deep bass sound booster device.
 4. A deep basssound booster device as claimed in claim 3, wherein the switch is turnedon when the first and second sound output signals are added together andfed out of the deep bass sound booster device by way of the first outputterminal, and the switch is turned off when the first and second soundoutput signals are separately fed out of the deep bass sound boosterdevice by way of the first and second output terminals, respectively. 5.A deep bass sound booster device comprising: two processing blocks, eachcomprising: an input terminal by way of which an input sound signal isfed into the deep bass sound booster device; a high-pass filter to whichthe input sound signal is fed from the input terminal and which permitsonly a frequency component higher than a predetermined frequency to passthrough so as to output a resulting signal as a first sound outputsignal; a bass booster to which the input sound signal is fed from theinput terminal and which amplifies only a frequency component lower thanthe predetermined frequency and attenuates another frequency componentso as to output a resulting signal as a second sound output signal; aswitch to which the signal output from the bass booster is fed at oneend and which, when turned on, outputs that signal at another end; afirst adder to which the signal output from the high-pass filter is fedand to which the signal output from the switch is fed, the first adderadding together those two signals and outputting a resulting signal; anda first output terminal by way of which the signal output from the firstadder is fed out of the deep bass sound booster device; and a secondadder to which two signals output respectively from the high-pass filterof each of the two processing blocks are fed and which adds those twosignals together and outputs a resulting signal; and a second outputterminal by way of which the signal output from the second adder is fedout of the deep bass sound booster device.
 6. A deep bass sound boosterdevice as claimed in claim 5, wherein the switch is turned on when thefirst and second sound output signals are added together and fed out ofthe deep bass sound booster device by way of the first output terminal,and the switch is turned off when the first and third sound outputsignals are separately fed out of the deep bass sound booster device byway of the first and second output terminals, respectively.